If you use the Battle.net Mobile Authenticator and intend
to update
your iPhone or iPod touch to iPhone OS 3.0, we would like to highly
recommend that you first back up your iPhone or iPod touch to your
computer using iTunes prior to performing the update. By taking this
important precaution, you will be able to quickly restore your previous
install of the Battle.net Mobile Authenticator if you encounter any
issues during
the update process.
For more information, refer to the Battle.net Mobile Authenticator FAQ here: http://eu.battle.net/bma
Article Source: www.curse.com.